Assumption of the Blessed Virgin Mary Church in Żagań, Poland, is a Gothic church built between the fourteenth and second-half of the fifteenth century. The church is part of the Roman Catholic Diocese of Zielona Góra-Gorzów. It is listed as a Historic Monument of Poland.

It is one of the burial sites of the Piast dynasty, including Henry IV the Faithful, Henry V of Iron, Henry VII Rumpold, Henry VIII the Sparrow, Jan I of Żagań, Balthasar of Żagań.